1. Field of the Invention
The subject matter of this invention is related generally to molded case circuit breakers and more specifically to handle mechanisms for molded case circuit breakers.
2. Description of the Prior Art
Molded case circuit breakers and interrupters are well known in the art as exemplified by U.S. Pat. No. 4,503,408 issued Mar. 5, 1985, to Mrenna et al., and U.S. Pat. No. 5,910,760 issued Jun. 8, 1999 to Malingowski et al., each of which is assigned to the assignee of the present application and incorporated herein by reference.
Separately attachable handles for circuit breakers are known. In most cases these are devices which are disposed on the front of a molded case circuit breaker and convert the rotary or pivotal motion of a rotary to the linear or translational motion of the typical circuit breaker linear action handle. The rotary handle is mounted parallel with the plane of the faceplate of the molded case circuit breaker, but spaced outwardly from it by the dept of the handle mechanism. Usually a series of linkages or gears are utilized to interconnect the rotary motion of the rotary handle to the linear motion of the circuit breaker handle. There are a number of disadvantages associated with the previous rotary handle mechanism. One disadvantage lies in the fact that for very small circuit breakers, the mechanical advantage of the rotary handle is reduced by the necessary small length of the lever arm of the handle. Also, it is common for electricians to lock the circuit breaker handle in place on the circuit breaker handle mechanism front cover, when performing service work, to be assured that the circuit breaker contacts are open so that the safety of the electrician is also assured. In order to do this, the handle has to be large enough to accommodate as many as three lock hasps in the eventuality that three electricians may be working downstream of the circuit breaker in question. It is also desirable to provide an indication of the status of the circuit breaker in a most elementary way, so that an observer can tell whether the circuit breaker is conducting electrical current or blocking electrical current.